c1 Transportation Asset Management Case Studies

CULVERT MANAGEMENT SYSTEMS

Alabama, Maryland, Minnesota, and Shelby County

Presented by
The need for better culvert management is apparent.

Photography Credits 

Photographs courtesy of Federal Highway Administration, 

Maryland State Highway Administration, Minnesota Department 

of Transportation, New York State Department of Transportation, 

and Shelby County Highway Department
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Note From the Associate Administrator 

With factors such as an aging and deteriorating national infrastructure, increasing congestion, highway safety

challenges, and limited funds weighing heavily on transportation agencies, State departments of transportation

are looking for innovative ways to manage their transportation dollars.

One tool that is providing great benefits is Transportation Asset Management (TAM), a strategic approach

that strives to provide the best return for each dollar

invested by maximizing system performance, improving

customer satisfaction, and minimizing life-cycle costs. 

TAM implementation varies from State to State and

include the areas of bridge and pavement management,

highway safety and operations, data integration, economics in asset management, life-cycle cost analysis, and

network preservation, among others. TAM is also beginning to include often overlooked highway features such

as sign structures, culverts, and retaining walls.

Because each State’s experience is unique—and

because the Federal Highway Administration believes

that transportation agencies work more efficiently when

information on one another’s successes is shared—the

Office of Asset Management is continuing its series of

TAM case study reports begun in 2002.

On behalf of the Office of Asset Management, I am

pleased to present this case study on culvert management

systems (CMSs). Although sometimes included as part of

bridge management systems, culverts are not always

given the attention they require. This case study details

the efforts and methods of three States and one local

agency in implementing a CMS. I believe that this and

other case studies generated by the Office of Asset Management will help transportation agencies meet the

increasingly complex challenges facing them today.

King W. Gee

Associate Administrator for Infrastructure

May 2007
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Note to the Reader

The Transportation Asset Management Case Study series is the

result of a partnership between State departments of transportation (DOTs) and the Federal Highway Administration

(FHWA) Office of Asset Management. FHWA provides the

forum from which to share information, and the individual

States provide the details of their experiences. For each case

study report, FHWA interviewed State transportation staff, and

the resulting material was approved by the State. As such, the

reports rely on the agencies’ own assessment of their experience. Readers should note that the reported results may or

may not be reproducible in other organizations. ■
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Executive Summary 

State and local DOTs are responsible for a large number of

highway assets. Many of these assets, such as bridges and

pavements, are highly visible and have dedicated management

systems. Highway agencies also have many less noticeable

structures, such as culverts, that tend to go ignored until a catastrophic failure occurs. Unfortunately, several catastrophic

failures have occurred across the United States, emphasizing

the need for a culvert management system (CMS). Some

States have utilized the CMS program developed by FHWA,

while other States have created in-house programs to meet

the specific needs of their area. 

By taking a proactive role in managing culverts, States are

preserving their investment in the transportation infrastructure and providing a safer roadway for the traveling public.

Maryland, Minnesota, Alabama, and Shelby County (located

in Alabama) use different methods to manage their culverts.

This study explores their methods and offers information to

agencies seeking new approaches to culvert management.

Maryland has divided the responsibility for its culverts

based on size. Large culverts are the responsibility of Maryland’s bridge unit, while small culverts are under the auspices

of the State’s roadway unit. Although Maryland no longer

utilizes Pontis (a comprehensive bridge management system

[BMS] tool), it applies the condition ratings from Pontis to its

own in-house CMS for large culverts. Maryland has also

developed a risk-based approach to selecting which structures receive priority for inspections, which helps to reduce

inspection costs. For the smaller structures, the roadway unit

uses a separate in-house inspection and rating system that

incorporates geographic information system

(GIS) tools.

Like Maryland, the Minnesota DOT divides

the responsibility for its culverts between the

bridge hydraulics unit and the roadway unit

based on the size of the culverts. However,

unlike Maryland, Minnesota uses Pontis along

with element-level condition ratings to manage

the larger culverts. The bridge hydraulics unit

has developed an in-house GIS-based program

called HYDINFRA, which is used for culverts and

other types of drainage features, such as drop

Because of their potential for 

catastrophic failure, culverts require

careful management.
4

inlets. The bridge hydraulics unit has also developed an inspection guide complete with condition rating language for use

with HYDINFRA.

In Alabama, the DOT’s maintenance bureau manages the

State’s culverts, and maintenance personnel inspect these

structures on an as-needed basis. The current maintenance

management system is scheduled to be updated in the near

future, which could provide an excellent opportunity to develop an in-house system or commence use of a formal CMS.

Typically, Asset Management case studies focus on the

activities of State DOTs rather than local agencies. However,

the Shelby County Highway Department was found to have a

very proactive approach to culvert management. While the

county’s inventory is not as large as that of a State DOT, Shelby County uses the FHWA CMS program. Shelby County has

been a leader in the State of Alabama in promoting Asset

Management on a county level and educating other counties

using the program. Shelby County DOT has taken the initiative to partner with academia and industry and has utilized

Asset Management principles to help determine budget and

replacement priorities for highway structures in this fastgrowing county.

This overview of the culvert management practices used by

these DOTs is presented to show the importance of managing

these drainage structures. It is also intended to help other State

and local DOTs formulate and shape their Asset Management

programs in ways that lead them to achieve their goals and performance measures efficiently and cost-effectively. ■
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BACKGROUND

Asset Management is presently a key focus area for many transportation

agencies in the United States and abroad. Asset Management merges quality asset data with well-defined objectives to help improve a transportation

department’s business process for resource allocation and utilization. In

short, Asset Management is a strategic approach to managing transportation infrastructure.

The American Association of State Highway and Transportation 

Officials (AASHTO) Subcommittee on Asset Management defines Asset

Management as a strategic and systematic process of operating, maintaining,

upgrading, and expanding physical assets effectively throughout their lifecycle.

It focuses on business and engineering practices for resource allocation and 

utilization, with the objective of better decision making based upon quality

information and well-defined objectives.1

Asset Management typically relies on data from the following management systems:

• Bridge management.

• Pavement management.

• Tunnel management.

• Ancillary structures management (i.e., sign structures, high-mast light

poles, retaining walls, and roadway appurtenances).

• Information management.

This case study examines different types of CMSs used by State and

county DOTs. The management systems include the Pontis BMS, the

FHWA CMS, and a State-developed system.

In order to determine the characteristics of a well-functioning CMS,

the study focuses on the following aspects:

• Inventory. 

• Inspection.

• Management and documentation.

• Planning, budget, and decision-making methodology.

1 http://www.transportation.org/sites/scoh/docs/Motion_Trans_Asset_Management.doc.

Retrieved May 2, 2007.
6

Using a CMS assists a DOT not only in keeping track of its assets but

also helps with prioritization of rehabilitation, repair, and replacement of

structures. Prioritization in turn helps to optimize the use of the limited

amount of funds a DOT may have available for culverts.

CASE STUDY

In reality, every DOT practices some form of Asset Management. However,

the differences lie in the sophistication of data collection and management

systems, and how they are employed in budgeting and decision-making

processes. 

Based on a questionnaire sent to FHWA division bridge engineers (see

Figure 1), only 29 States have some sort of CMS, 8 report using Pontis, 

13 are using an in-house program, and 8 are using some combination 

of systems for small structures and culverts under 20 ft in length. These

combinations include using Pontis for some lengths and an in-house 

program for the remainder. Some in-house systems are quite sophisticated

and include GIS capabilities, while some use simple spreadsheets and 

databases. Twenty-three of the States do not have a CMS. This case 

study highlights the use of different management systems in Maryland,

Minnesota, Alabama, and Shelby County. The experiences of these transportation agencies are presented to encourage more States to implement

culvert management. 

FHWA CULVERT MANAGEMENT SYSTEM 

(FROM THE USER’S MANUAL)

The FHWA CMS was developed in 2001 under the Local Technical Assistance Program to assist road agencies in managing their programs of culvert

inventory and condition assessment and improvement. The purpose of this

program is to provide a tool to facilitate the coordination of maintenance

and repair or replacement operations on a system-wide basis. 

The CMS formalizes and automates functions already performed by

many agencies responsible for culverts. The program assists DOTs with:

• Recording the number and location of culverts for which the agency 

is responsible.
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• Tracking the condition of the culverts.

• Determining what repairs are necessary to fix the culverts.

• Developing a long-term plan for repairs over the next 5 years.

• Formulating a schedule of work to be performed during the next year.

The CMS consists of five modules to aid the user in managing the

inventory of culverts:

1. Inventory module.

2. Condition module.

3. Maintenance and Repair module.

4. Work Funding module.

5. Schedule module.

NV

8

0

HI

WA

FL

TX

PR

TN

AZ

LA

NM MS

AR

SD

AL

MO

CT

OK

KS

GA

ND

KY

IL

UT

NC

WV

CO

MI

IA

CA

VA

ME

MN

IN

SC

MD

ID

NE

PA

NJ

DE

DC

RI

OH

WY

VT

WI NY

MA

Combination

FHWA Culvert Management System

In-house developed

Pontis

None

Local agency using FHWA CMS

OR

MT

AK 

NH

13

8

23

Figure 1. State usage of culvert management systems as of January 2007, based on a

questionnaire sent to FHWA bridge engineers.
8

The Inventory module (see Figure 2) is a simple database storage and

retrieval tool used primarily to supply information directly to users of the

system and to other modules of the CMS. The inventory information is

typically gathered from design and construction plans and from field verification and helps DOTs answer the question of “how many culverts do

we have?” Information such as location, size, material type, and structure

ID number is stored here. This module also allows users to enter new

structures, delete structures that have been replaced, and obtain a detailed

culvert description report. A search for culvert structure records can be

performed in each module based on the culvert’s unique structure ID. 

The Condition module (see Figure 3) is used to enter and store information related to the condition of the culverts based on visual inspections.

This information is used to develop work needs, costs, budgets, and schedules. The condition is rated on 17 different items, including inspection

dates, overall condition rating, hydraulic adequacy, proposed repair types,

and roadway condition. The inspection identifies the maintenance and

rehabilitation activity to be performed to correct the condition in addition

to the quantity of work required.

The Maintenance and Repair module (see Figure 4) develops the total

work needs and costs for all work identified in the Condition module.

This module has two parts: 

1. Defining the work to be performed.

2. Developing the work needs and costs. 

The work performed or maintenance and rehabilitation activities

include items such as debris removal, scour hole repair, vegetation control,

and joint sealing. The module then takes the work needs from the Condition module and applies unit costs to the work quantity. 

The Work Funding module uses the work needs developed in the previous module to create a multi-year list of funded projects prioritized by

repair type. The procedure uses a series of factors, defined by the user, that

takes into account such items as priority, cost, remaining life, traffic, and

hydraulic capacity to rank projects, and determines the projects that can 

be done that year using available funds. It also indicates the projects that

cannot be undertaken due to lack of funding. 

The Schedule module allows the user to schedule the programmed

work for the year. The scheduling process takes the work programmed
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Figure 2. Inventory module.

Figure 3. Condition module.
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from the Work Funding module and, using the constraints of labor, 

dollars, and pre-scheduled projects input by the user, establishes when 

the various culvert projects can be performed. In the scheduling process,

all of the activities within a project will be performed at the same time.

By using the FHWA CMS program to track culvert inventory, 

condition, and cost information, an agency can better manage its culvert

program. This systematic process will help the agency to prioritize repair

and replacement decisions and maximize the limited resources it has to

expend on culverts. 

MARYLAND

In Maryland the responsibilities for inspection and management of Stateowned culverts belong to the State Highway Administration (SHA). The

SHA has seven engineering districts, each encompassing several counties.

Each district has a headquarters office, which is responsible for managing

highway and bridge construction contracts, as well as all maintenance

functions, including pavement and bridge repairs. Headquartered in 

Figure 4. Maintenance and Repair module.
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Baltimore, the SHA is responsible for more than 2,500 bridges and more

than 16,000 lane-miles of interstate, primary, and secondary roads. In

1996, the agency assumed responsibility for the management and routine

monitoring of small structures, including culverts, as a proactive measure.

Although no collapse or other event prompted the routine monitoring, 

the SHA recognized that some smaller structures had structural problems

that could lead to failure or other serious consequences. 

Division of Responsibilities

Within the SHA, the responsibility for culvert management and inspection is divided between the Bridge Inspection and Remedial Engineering

Division (BIRED) and the Highway Hydraulics Division (HHD). BIRED

is part of the Office of Bridge Development, and HHD is part of the

Office of Highway Development. Both offices operate under the deputy

administrator/chief engineer for planning and engineering. Figure 5 

illustrates the SHA hierarchy.

Maryland State Highway Administration

Deputy Administrator and Chief Engineer 

for Planning and Engineering

Office of Highway Development

Highway Hydraulics Division 

Responsible for culverts < 5 ft

Office of Bridge Development

Bridge Inspection and Remedial 

Engineering Division

Responsible for culverts 6 5 ft 

and culverts between 3 and 5 ft 

that meet fill height requirements

Figure 5. Maryland State Highway Administration hierarchy.
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The division of inventory and inspection responsibilities is based on 

culvert size. BIRED typically inspects the larger structures, while HHD

handles the smaller sizes. All culverts down to a 5-ft span are inventoried

and inspected by BIRED, regardless of height of fill. Culverts from 3 to 5 ft

in span are selected for inventory and inspection as follows:

• If the fill height is less than the span length, the culvert is inventoried

and inspected at a regular frequency. 

• If the fill height is greater than the span length, the culvert is not 

inventoried or inspected. 

This selection process incorporates hazard levels, or consequences of

failure, into the inventory and inspection policy. Based on experience, the

SHA recognizes that the consequences of failure of a pipe under a small

amount of fill are greater than one under a larger fill. A variation of this

approach also applies to a battery of culvert pipes. Culverts in Maryland

are primarily made of steel or concrete; however, some of the older culverts

are made of stone or brick masonry. Although there are a few plastic pipes

in the inventory, they are seldom used. 

The district offices typically handle routine culvert repair and minor

maintenance concerns, such as debris removal. Contract forces sometimes

assist with maintenance. After the inspection crew notifies the district

office of necessary repairs and maintenance, the district prioritizes the

work. The central office is responsible for major repairs that may require

an engineered fix. The central office prioritizes the work and creates a daily

structure repair work list. Contractors assist the central office by undertaking substantial repairs, such as invert paving and shot-creting. 

Most culvert replacements are handled as individual projects, but a few

are done as part of corridor improvement projects. Although BIRED does

not typically become involved in corridor improvement projects where a

series of culverts is replaced, HHD sometimes considers drainage improvements to highway corridors where a series of culverts would be investigated

for design (capacity) adequacy. Replacements of culverts with spans greater

than 5 ft are typically performed by contractors. State maintenance crews

occasionally perform smaller culvert pipe replacements. 

The Maryland Department of the Environment (MDE) is concerned

about fish passage and water quality and therefore requires permit approval

for any in-water work, including repairs, replacements, scour counter-
13

measures, or culvert linings. HHD must follow the same MDE rules for

permitting as BIRED does. However, fish passage is not as much of an

issue for smaller structures. 

Inventory and Inspection

When fully staffed, BIRED has 18 full-time in-house bridge inspectors

who conduct culvert and small structure inspections in addition to 

performing bridge inspections in accordance with the National Bridge

Inspection Standards (NBIS). The inspectors have taken the 2-week bridge

inspection course sponsored by the National Highway Institute (NHI),

and some have taken the bridge inspection refresher course. Local agency

inspectors responsible for small structures typically do not have this 

training. 

Although the SHA has a bridge inventory manual, Maryland does not

have an inspection manual for bridges or culverts. The SHA is working to

complete a policy and procedures manual, which will include formalized

bridge inspection procedures. Culvert condition ratings are based on NBIS
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Item 62 using a scale of 0 to 9. Also,

Pontis element-level inspection ratings

and condition-state language are used

in inspection reports.

BIRED typically inspects culverts

on a 4-year cycle, although inspection frequency can be increased 

to a 2-year cycle if the condition

warrants. When possible (i.e., when

the culvert is large enough, daylight is visible at the outlet, and access 

is not blocked by debris), culverts are manually inspected through the

length of the barrel. BIRED has inventoried approximately 3,600 culverts since 1996. 

HHD typically inspects culverts and pipes in the range of 36 to 60 in.

and some up to 72 in. depending on the county and the highway classification, but does not inspect locally owned pipes. HHD also inventories

drop inlets that are at the ends of the cross culverts and is inventorying

these structures statewide. From the counties inventoried thus far, the

SHA estimates that there are 10,000 culvert pipes in each rural county and

15,000 culvert pipes in each of the more urban counties—approximately

287,500 culvert pipes throughout the State’s 23 counties. 

HHD uses a different set of inspectors from BIRED. The inspectors

are technicians but are not required to have any NBIS training. These

inspectors receive in-house training from HHD based on HHD standard

operating procedures. Inspectors generally inspect during dry weather

and, in addition to looking for structural defects, use visual inspection

techniques to detect latent discharge through the culverts. Inspectors can

do basic pH tests on the water if a latent discharge is detected. Additional

inspections may be conducted based on the reports or requests from 

district maintenance staff.

Prioritization

Culvert replacement is prioritized based on current condition, perceived

consequences of failure, current use, and other factors. The “EPABCD”

system is used as a tool to prioritize replacement, with an “E” code receiving the most consideration and a “D” code receiving the lowest priority.
15

“E” refers to an emergency situation requiring immediate action. “P” refers

to a personal or political preference. Priority continues to decrease from

“A” through “D.” Culvert repairs are conducted on an as-needed basis,

typically by contractors, based on the EPABCD system, with items such 

as leaking joints typically receiving the highest priority.

Replacement of the smaller structures is prioritized based on the following criteria:

• Highway classification: 

– Interstate highways. 

– Higher classified State or U.S. routes. 

– Other State routes. 

• Available resources (manpower and financial). 

• Project complexity. 

• Upcoming corridor improvements.

• Worst first. 

The repair priority is based on a weighted system. Several of the

weighted areas are highway safety, flooding, and drainage complaints. The

culverts with the highest weighting are given first priority (i.e., worst first).

Priority is also given to joint and erosion repairs. Some districts will make

repairs based on their level of expertise and available manpower; otherwise,

repairs are conducted by contractors. 

HHD bases culvert condition ratings on a scale of 0 to 5. Zero signifies

no rating, 1 means that no action is required, and 5 indicates that emergency repair is needed. The intent is to have these structures inspected 

on a 3-year cycle concurrent with their National Pollutant Discharge 

Elimination System (NPDES) cycle. 

Databases

Rather than using the CMS developed by FHWA, BIRED tracks culverts

that meet the size and fill requirements in an in-house Access database,

referred to as a Structure Management System (SMS), which is also used

for NBIS-length bridges. The SMS does not predict culvert service life 

as a function of existing or anticipated deterioration. 

HHD developed an in-house, Access-based GIS for inventory 

(see Figure 6). Because of the large amount of data being stored in the 
16

inventory, HHD will eventually convert to an Oracle-based GIS. This

database is separate from the BIRED bridge database, although there 

may be some small overlaps with culverts in the 60 to 72 in. range. 

Funding

Although BIRED does not have funding dedicated specifically for culverts,

financial support for the repair and replacement of culverts comes from

the operating budget. On an annual basis, the SHA budgets $350,000 for

its bridge inspection program, which includes NBIS bridges and small

structures. For culvert repairs and replacements, BIRED spends approximately $500,000 per year; however, BIRED spent $1.7 million in 2005

and $2.4 million in 2006 on paving deteriorated steel pipe inverts.

HHD has a dedicated budget, established within the last 2 years, for

addressing drainage improvements. The budget allocates system preservation dollars for the replacement of culverts. HHD anticipates that this

budget will be in effect for at least the next 6 years.

Figure 6. In-house, Access-based geographic information system used by the Maryland

State Highway Administration’s Hydraulics Unit.
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Conclusion

The Maryland SHA has taken a proactive stance in creating its culvert

inventory and inspection program. It has successfully balanced the time

and cost of inspecting these numerous structures with a comprehensive

risk-based approach. This allows the SHA to minimize potential hazards 

to the traveling public. Although the agency already has a well-established

program, it may be receptive to the idea of national inspection standards

for culverts and small structures with accompanying Federal funds. The

SHA prefers an in-house database over the CMS software developed by

FHWA, but is willing to consider an updated CMS in the future.

MINNESOTA

In Minnesota the responsibilities for inspection and management of Stateowned culverts belong to the Minnesota DOT (MnDOT). MnDOT has

eight engineering districts, each encompassing several counties; each district

has a headquarters office. Most of MnDOT’s day-to-day operations are

managed at the district level, including highway construction projects and

maintenance. MnDOT, headquartered in St. Paul, is responsible for more

than 11,000 lane-miles of the State-owned trunk highway system and 

more than 3,800 bridges. With its additional 123,000 lane-miles of local

highways and 9,800 local bridges, Minnesota has the fifth largest highway

system in the Nation. 

Division of Responsibilities

Within MnDOT the responsibility for culvert management and inspection

is divided between the Bridge Inspection Unit and the Hydraulics Unit.

Both units are part of the Bridge Office headed by the State bridge engineer. Figure 7 illustrates the MnDOT hierarchy.

The division of inventory and inspection responsibilities is based on 

the size of the culverts. The Bridge Inspection Unit is responsible for the

inspection of structures that span more than 10 ft, while the Hydraulics

Unit handles structures that span less than 10 ft. Culverts and pipes down

to a 12-in. diameter are inventoried and inspected by MnDOT district

personnel based on district priorities and resources. 
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Small culvert replacement, repair, and maintenance are done by both

State forces and contractors. Most of the replacements and rehabilitations

occur during corridor improvement projects. Slip lining and cured in-place

liners are the most common rehabilitation methods. Replacement methods

are most commonly open trench and occasional jacking, which is the horizontal placement of pipes by driving the pipe through an embankment.

Culvert replacements of all sizes on public waters require a Department

of Natural Resources (DNR) permit. MnDOT has a general permit with

the DNR for crossings of public waters. Fish passage is a concern for larger

culverts on public waters.

Inventory and Inspection

The culverts on the State trunk highway system that span more than 10 ft

are inspected on a 12- or 24-month frequency depending on the condition

Minnesota Department of Transportation

Deputy Commissioner/Chief Engineer

for Planning and Engineering

Engineering Services Division

Bridge Office

Bridge

Inspection Unit

Responsible for

culverts > 10 ft

Hydraulics Unit

 Responsible for

culverts < 10 ft

District Operations Unit

District Offices

Figure 7. Minnesota Department of Transportation hierarchy.
19

of the structure. Minnesota State law does not allow for inspection at

intervals greater than 2 years; however, MnDOT is currently working to

amend the law to allow a 4-year frequency on some structures, especially

concrete box culverts. The Bridge Inspection Unit has been inventorying

culverts longer than 10 ft since the early 1970s. Most of the approximately

10,500 culverts are made of steel and concrete, with some masonry, 

timber, and aluminum structures scattered throughout the State. These

inspections are conducted by NBIS-certified inspectors.

Minnesota does not have a required inspection frequency for culverts

less than 10 ft; therefore, each district can determine its own frequency.

Most districts have chosen to inspect a number of these smaller structures

on an as-needed basis. If the culverts are in an outfall in a Municipal Separated Storm Sewer Systems for Pollution Control area (MS-4), 20 percent

of the culverts are required to be inspected each year. 

Although the inspectors for these smaller structures are not required to

have any NBIS training, most participate in a 1-day course focusing on

condition, codes, problems, and data formatting. Inspections of smaller

structures are conducted by district maintenance and hydraulic personnel,

as well as contractors hired and supervised by the district. Individualized

training is provided for district staff, while formal classes are held as needed for contractors. For a company to qualify for consultant work, two of

its people must attend the formal training. Most culverts are inspected

visually using flashlights. Video inspection is used on occasion. 

Maintenance and repair of culverts, including extending culverts and

placing pipes inside old box culverts, are carried out by both State forces

and contractors. 

Prioritization

The Bridge Inspection Unit prioritizes work on large culverts according to

inspection condition ratings based on both Pontis and NBIS. The central

Bridge Office is responsible for developing a needs assessment for the

State-owned culverts spanning 10 ft or more in each district. The needs

assessment covers short- to long-range budget needs in 7- to 9-year increments. The current needs assessment covers the following time frames:

• Short term: 7 years (2008–2014).

• Mid range: 9 years (2015–2023).

• Long term: 7 years (2024–2030).
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Once the statewide needs are determined, the central Bridge Office 

prepares a list of recommended projects for each district. The districts

must select which projects to fund and prioritize their selections. 

The Hydraulics Unit has developed a culvert inspection guide that 

contains condition rating information and condition-state language. 

The ratings are based on a scale of 1 to 4, with 1 being the best condition

and 4 meaning an immediate fix may be required. For the districts, pipes

with a rating of 4 (emergency pipes) are top priority. Additionally, pipes

with a condition rating of 3 will be fixed as time and resources permit. 

For corridor projects, pipes rated as 3 and 4 are reviewed and prioritized 

as part of the project scope. 

Databases

In addition to the division in responsibilities, two different computerized

management systems are used, Pontis and HYDINFRA. 

Pontis

For inventory and management of the larger structures, the Bridge Inspection Unit uses Pontis. Although intended primarily for bridges, the software

can be used by a DOT to manage its inventory of culverts. Pontis has the

capability to predict deterioration and remaining service life and to make

repair and rehabilitation recommendations. 

HYDINFRA

The impetus for the development of HYDINFRA (HYDraulic INFRAstructure) came from the district hydraulics engineer’s decision to create a

management system for the hydraulic infrastructure on a statewide level.

Development of HYDINFRA began in 1996 and was completed a year

later. Prior to this, each district either did not collect data for small culverts

or had its own way of inventorying and collecting data from paper records

to simple databases. Fortunately, there was no catastrophic failure or event

that prompted the MnDOT to manage these structures.

HYDINFRA catalogs several types of hydraulic features, as illustrated

in Table 1. Although MnDOT does not differentiate culverts from storm

drains, there are approximately 50,000 pipes in the inventory. MnDOT

estimates that 75 percent of the State-owned pipes have been inventoried.
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Other than steel and concrete, the inventory has some plastic and corrugated 

aluminum pipes. 

HYDINFRA manages both inventory

and inspection data for each hydraulic 

feature. Examples of inventory and 

inspection data are shown in Table 2.

HYDINFRA data is used primarily for

construction project scoping and to plan

maintenance and repairs. Survey crews have

used HYDINFRA data to locate culverts

for more detailed mapping work. Beginning in 2006, HYDINFRA was used to

find features requiring maintenance under

the new water quality requirements. Inspection and maintenance activities are logged

by date so that the history of problems or

repairs is available for each feature.

Table 1. Hydraulic Features Cataloged in HYDINFRA 

Hydraulic Feature Examples

Pipes Culverts spanning between 12 in. and 10 ft

Storm drains

Structures Drop inlets

Catch basins

Manholes

Special structures Aprons

Headwalls

End treatments

Weirs

Increasers/reducers

Water quality devices Pond

Ditch

Structural pollution control device

Illicit discharge

Outfalls

Virtual features (added in 2006 to facilitate 

record keeping for National Pollutant Discharge 

Elimination System requirements)

A field inspector uses a global 

positioning system receiver to 

collect data that will be recorded 

in HYDINFRA.
22

Field inspectors collect data with global positioning system (GPS)

receivers, and the data is then uploaded to an Oracle database. Geographic

information tools allow users to query the database for specific information and create maps for use in various projects (see Figure 8). Users can

query by condition, need for repair, or need for cleaning. 

Users can access HYDINFRA reports to obtain detailed information

about culverts in a specific geographic area. The Pipe Inventory and

Inspection Report allows users to specify a highway and the beginning and

ending milepost for the area of interest. The report lists information, line

by line, about the set of pipes along that stretch of highway (see Figure 9).

Data include size, shape, material, and location, plus condition ratings and

detailed attribute flags that note problems in the pipes. 

Oracle forms allow for data creation, editing, and access. Advanced

users complete the Batch Review Form to view newly loaded data 

(see Figure 10). Forms also interact with the ArcGIS HYDINFRA tools, 

allowing data to be selected in GIS and viewed in forms and vice versa.

Funding

The cost of replacing large culverts is covered by the statewide general

structures budget. There is no dedicated budget for small culverts. The

Table 2. Examples of Inventory and Inspection Data

Types of Data Examples

Inventory data Location

Type

Initial size

Shape

Material

Inspection data Condition code

Need for repair

Need for cleaning

Condition attribute flags

Maintenance repairs accomplished and other changes 

over the life of the hydraulic feature

Plan data for proposed features
23

funds are allocated from the general roadway budget to the districts, who

then prioritize projects and decide which to undertake. 

For local structures, funding comes from the State gas tax, township

bridge funds, and bonding. Counties and municipalities set their own

budgets, select their own projects, and handle their own designs. On

occasion, MnDOT offers assistance with large, complex, or unique 

structures.

Conclusion

In the absence of any Federal requirements, MnDOT has developed 

procedures and guidelines for inspection of its massive inventory of culverts and drainage structures. Although the management responsibilities

are divided between two units within the Bridge Office that utilize two

different management tools, MnDOT has a good handle on its small

structure inventory. The use of Pontis is a practical application of an 

Figure 8. HYDINFRA geographic information system tools.
24

existing software package for CMS purposes. For the smaller structures,

HYDINFRA can be used as a model for other States for managing their

drainage systems. MnDOT has expressed a willingness to share information on their HYDINFRA with other DOTs. This evolving tool is 

consistently being enhanced to take advantage of the new developments

in computer technology.

MnDOT sees no need for 

a Federal mandate to inspect 

culverts, especially since the State

has already developed its own

procedures. In fact, MnDOT

maintains that a Federal mandate

could be a burden to local governments. This view is consistent

with the position already adopted

in 2005 by the AASHTO 

Subcommittee on Bridges and

Structures.

Maint. CleanMaint. RepairRepair Under RoadPluggedDeformedStanding WaterInfiltration

Figure 9. MnDOT Hydraulic Infrastructure Pipe Inventory, Inspection, Maintenance 

on MN210 from MP178.00 to 210.00 

Status: In Place or Purposed 

Pipe ID MP Cond Pipe Material Length Span Cover

Shape x Rise

588875 182.79 2 Box Concrete 47.0 ft 72x48 in. 2–6 ft Y NNNNNN

588876 183.82 2 Round Concrete 72.0 ft 24x24 in. 2–6 ft Y NNNNYN

588877 185.05 2 Box Concrete 57.0 ft 60x60 in. 2–6 ft Y NNNNYN

588878 185.58 4 Round Concrete 84.0 ft 24x24 in. 6–10 ft N Y N YYYY

588879 185.83 4 Round Concrete 75.0 ft 24x24 in. 6–10 ft N Y N Y Y N Y

588880 186.07 4 Round Concrete 66.0 ft 24x24 in. 6–10 ft N Y N Y Y N Y

588881 186.96 2 Round Concrete 98.0 ft 30x30 in. 10–20 ft Y NNNNNN

Figure 10. Oracle form used by MnDOT.
25

ALABAMA

In Alabama the responsibilities for inspection and management of Stateowned culverts belong to the Alabama DOT (ALDOT). ALDOT has 

nine geographic divisions. Each encompasses several counties and has a

headquarters office. Each division is responsible for managing highway 

and bridge construction contracts, as well as all maintenance functions,

including pavement and bridge repairs. The divisions are further subdivided into districts with, typically, three to six districts within each division.

ALDOT, headquartered in Montgomery, is responsible for more than

5,600 State-owned bridges.

Division of Responsibilities

The maintenance engineer in each of the ALDOT divisions is responsible

for the inspections. Typically, these inspections are delegated to the districts. Figure 11 illustrates the ALDOT hierarchy. 

Although culvert replacements and repairs can be part of a corridor

improvement project, most are replaced individually. State forces primarily

perform culvert maintenance and replace some minor drainage structures.

ALDOT also handles culvert relining and filling with flowable fill, culvert

Silt PresentPipingCracksSpalling/FlakingPitting/RustingMisalignmentJoints SeparationHolesInslope CavityRoad VoidRoad StressErosion

Inspection 

Date

YNNNNNNNNNNN 6/29/2006

YNNNNNNNNNNN 6/29/2006

YNNNNNNNYNNY 6/29/2006

YYY YYYYYN 6/30/2006

YY YYYYNNY 6/30/2006

YYY YYYYNNY 6/30/2006

YNNNNNNNNNNN 6/30/2006
26

extensions, and some invert paving. The majority of the work—more than

90 percent—is completed by contractors. 

Culverts are typically installed at least 1 ft below the flow line to allow

siltation to occur and to provide a “natural” bottom for fish passage and

other aquatic species. ALDOT has recently created a section that handles

water quality and environmental issues for all maintenance activities. 

Permits are required from the Alabama Department of Environmental

Management (ADEMS), U.S. Army Corps of Engineers, U.S. Fish and

Wildlife Service, and other environmental agencies.

Inventory and Inspection

All culverts and pipes ranging from 20 ft down to 15 in. are inventoried.

The ALDOT Maintenance Bureau arranges this inventory of approximately

184,775 minor drainage structures by highway segment. Highway segments

Chief Engineer

Bureaus

Maintenance

Engineer

Bridge Inspection

Bridge Engineer

Divisions

Division Engineer

Maintenance Engineer

Culvert Inspection

Figure 11. Alabama Department of Transportation hierarchy.
27

vary in length based on the type of roadway (i.e., rural or urban sections)

or location (i.e., county or municipal sections). The count includes all 

of the minor drainage features along that roadway section and does not

distinguish between different types or sizes of culverts. The vast majority 

of culverts in Alabama are made of steel or concrete. Some of the other

structures are high-density polyethylene plastic.

Although ALDOT has not established a set frequency or cycle for

inspections, the ALDOT Maintenance Manual recommends annual

inspections if deemed necessary by the district engineer. After major rainfall or flooding, district roadway personnel conduct inspections by riding

the highways and looking for any problems, such as ponding water, 

erosion, dips in the roadway, and other signs of distress. These inspections

are for State-owned structures only and do not apply to local agencies. 

The ALDOT employees who perform the culvert inspections are not

required to have any formal bridge inspection training based on the NBIS.

Inspections are not based on a formal rating or NBIS system, and formal

inspection reports are not written. Since inspections are conducted as

needed and do not adhere to a formal cycle, there is no database of inspection information or reports to share.

ALDOT uses a bridge inspection manual but not a separate culvert

inspection manual. The field operations and maintenance manuals address

but are not specifically geared toward culvert inspection. The inspections

are conducted with flashlights, and on some occasions video equipment 

is used at the discretion of the district engineer. ALDOT is considering

moving towards using video inspection for all of its small drainage structure

inspections.

Prioritization

Instead of implementing a worst-first system for prioritizing culvert repairs

and replacements, ALDOT fixes problems as they develop based on

inspections.

Database

Instead of using the CMS software developed by FHWA, ALDOT has a

computerized inventory system and a computerized maintenance manage-
28

ment system. Developed in the 1970s, the maintenance management 

system can schedule future maintenance activities, but it cannot predict

deterioration, estimate costs, or prioritize replacements. ALDOT has committed to changing and updating the system within the next few years and

has expressed interest in a future version of the FHWA CMS software.

Funding

ALDOT has a dedicated budget for maintenance and inspection but does

not have a dedicated budget for culvert replacements. The typical amount

spent on culvert repairs and maintenance ranges from $1.5 to $2.5 million

annually.

Conclusion

Although no failure of a small or minor drainage structure has occurred

recently, ALDOT recognizes the importance of inventorying and inspecting these structures. The agency’s program, however, is more reactive than
29

proactive. ALDOT’s interest in a future version of the FHWA CMS may

lead the agency to develop a more formal system with official inspection

guidelines and frequencies. With a formal CMS, the agency could manage

its facilities more proactively and efficiently, possibly lowering the costs of

the inspection, repair, and replacement process. 

ALDOT welcomes Federal guidance for culvert inspection, but does

not support a mandate because the agency is already conducting inspections on its own terms. Adhering to the notion that States should have the

freedom to establish individualized standards, ALDOT prefers Federal

guidance rather than Federal standards.

SHELBY COUNTY

Shelby County, just south of Birmingham, is the fastest growing county 

in the State of Alabama. It encompasses approximately 800 mi2 in central

Alabama and is home to approximately 171,000 residents. Shelby County

Highway Department (SCHD), located in Columbiana, is responsible for

inspection and management of county-owned structures. SCHD is also

responsible for maintenance and construction of county roads, bridges,

guardrails, signs, and storm drains, and it provides engineering consulting

services to other county departments. SCHD handles the inspection of

180 NBIS-length bridges throughout the county. 

Division of Responsibilities

Approximately 11 years ago, the Shelby County engineer implemented

and funded an in-house bridge design and construction team. As a result,

most of the county’s culvert replacements are performed in-house with

specially trained and equipped county work crews. Less than 10 percent of

the SCHD’s LT20 Replacement Program has been performed by contract.

Typically, replacement projects have been scheduled in conjunction with

other rebuild elements such as widening, resurfacing, or intersection

improvements that have used Federal-aid funding. Local county work

crews under the supervision of a bridge inspector or bridge engineer 

typically perform culvert maintenance and repairs. Figure 12 illustrates 

the SCHD hierarchy. 
30

Inventory and Inspection

The SCHD began inventory of its culverts in 1994 following receipt of 

a statewide memo from ALDOT directing all counties to provide a count

of structures that are less that 20 ft (LT20) in length and have greater than

40 ft2 of drainage opening. About a year and a half later, in the summer 

of 1995, the county initiated its LT20 Replacement Program based on

recent inspections of structures less than 20 ft long. The 1995 inspections

revealed 90 small structures and culverts requiring replacement or rehabilitation. This LT20 Replacement Program was part of a countywide infrastructure improvement philosophy that included paving dirt roads, 

widening paved roads, and rehabilitation and replacement of NBISlength structures.

The county has 88 culverts and small bridges in its inventory. Most 

of the structures built in Shelby County in the 1960s through the early

1980s were made from treated timber. Almost all of these structures have

been replaced with reinforced concrete boxes or reinforced concrete pipes.

Steel and aluminum corrugated metal pipes (CMP) are only used for 

special applications, such as extensions of existing CMPs or for sliplining.

The LT20s are routinely inspected on a 4-year cycle; however, interim

inspections are performed after large storm events or reports of damage.

Operations Manager

Bridge Maintenance and

Construction Crew

Shelby County Engineer

Maintenance and

Construction Section Design Section

Chief Civil Engineer

Bridge Inspection

Figure 12. Shelby County Highway Department hierarchy.
31

For the last 6 years, Shelby County has been participating in various 

culvert management research and development programs, allowing 

inspections to occur on a regular 2-year interval in conjunction with the

NBIS inspection program. The condition rating system is based on NBIS

Item 62, which utilizes a scale ranging from 0 to 9, with 9 meaning “no

deficiencies” and 0 meaning “structure closed and needing replacement.”

SCHD employs trained and certified NBIS bridge inspectors in its

Engineering Department who perform inspections of all countymaintained NBIS and LT20 culvert structures in unincorporated Shelby

County and on county-maintained roads within municipal limits. 

Municipalities within the county are responsible for both NBIS and 

culvert inspection programs on their city-maintained streets, although

most municipalities contract their bridge inspections program to local 

consulting firms. 

Shelby County inspectors have attended the NHI-sponsored 2-week

training course for certification in bridge safety inspection, as well as the

annual ALDOT 2-day bridge inspection refresher courses. 

Although SCHD does not maintain a separate inspection manual, it

uses the available FHWA and ALDOT culvert inspection manuals and

other inspection resources. County inspectors are also encouraged to 

consult outside agency manuals available over the Internet such as the

Ohio DOT culvert inspection manual and the Montana DOT maintenance manual.

Shelby County has led Alabama in the innovative use of fly ash flowable fill, structural lining, and other low-impact, environmentally sound

culvert rehabilitation technologies. The county complies with the ADEMS

NPDES permitting and testing system on culvert replacement projects.

Generally, culvert replacements are below the reporting threshold for other

environmental concerns. The Shelby County Best Management Practices

Plan for reducing construction-related discharge in stormwater systems is

used. Fish passage is not an issue that is addressed on county projects at

this time.

Prioritization

SCHD utilizes both a modified worst-first replacement prioritization and

a corridor-improvements-driven replacement prioritization. Specific budgetary consideration is given to LT20s that are in a deteriorated state or are
32

approaching the end of effective 

service life by a ranking of overall

culvert condition. SCHD also

includes replacement or rehabilitation of existing structures in all of 

its road-widening and corridorenhancement projects. These projects

may be as significant as Federal-aid

projects sponsored by metropolitan

planning organizations or may be as general as county-funded road widening and resurfacing projects. SCHD has found that an “as you go” small

structure replacement protocol results in significant direct and user cost

savings while enhancing the appearance and overall safety of the local

roads network.

SCHD prioritizes its LT20 maintenance work in an increasing order 

of importance from routine repairs to preventative maintenance to major

rehabilitation to replacement. In addition, bridge inspectors are empowered

to categorize the maintenance activities requested as being “monitor, routine,

priority, urgent, or emergency.” Significant discussions are held between

Shelby County’s inspection and construction teams to ensure that specific

maintenance or repair items are assigned appropriate levels of importance.

Database

SCHD’s CMS consists of two parts:

1. The Inspection, Condition, and Maintenance and Repair modules of

the FHWA CMS.

2. A prioritization module developed in-house. 

SCHD is preparing to use the future deterioration and service life modules of the FHWA CMS. However, until this portion of the county’s culvert

database is operational, SCHD will continue to use its in-house-developed

prioritization module, which is based on overall culvert condition with

modifications to account for load posting, detour length, and average daily

traffic. In 2001 the SCHD completed an in-house deterioration and service

life module, known as the Local Roads Bridge Replacement Prioritization

Database (BRPD) system, that was initially used to prioritize the Shelby

County LT20 network of smaller structures and culverts. This system was
33

found to be worthwhile, although it would require further development

and enhancement before it could be easily utilized. The publication and

implementation of the FHWA CMS in 2001 effectively postponed the 

further development of the Local Roads BRPD system. 

SCHD has chosen to voluntarily collect and maintain its own LT20

inspection database. The benefits of this database have greatly outweighed

the commitment of time and resources required to initiate and maintain

the system. SCHD believes that its commitment to all facets of asset management have placed it in a position of national leadership among counties. SCHD recommends Federal guidance that will result in voluntary

participation through a system of grant rewards that could fund additional

innovative design and construction methods, composite materials research,

and application of computer technology to management solutions. SCHD

supports the establishment of national guidelines for culvert inspection,

and would be willing to participate in the preparation and implementation

of these standards. 

Recently, SCHD personnel led a culvert management seminar that

showcased the FHWA CMS to interested county and municipal engineers

in Alabama (see “FHWA Culvert Management Seminar,” UTCA Project

Number 05219, University of Alabama, 2006). Seminar participants

requested updates and technical corrections. System updates would be

beneficial to Shelby County and attractive to other potential users.

Funding

The Shelby County Commission permits the county engineer to designate

projects for funding on an annual basis. The project-specific designations

are subject to the ongoing prioritized needs as derived by the culvert management process. The net result is the dedication of a significant portion of

the budget for culvert replacement and maintenance activities. This budget

averages about $500,000 per year and includes funds for replacements,

repair activities, and preventive maintenance (see Figure 13).

Conclusion

Following the initial inventory mandated by ALDOT, SCHD has taken 

a practical, hands-on approach to maintaining and improving its culvert

inventory, inspection, and management system. It has taken the lead
34

among Alabama counties in promoting CMS by using and teaching CMS

principles. SCHD uses the FHWA CMS program and has identified areas

of the program that need to be improved and updated. SCHD has

expressed willingness to work with the FHWA in these efforts. Shelby

County has extended great effort to become a leader in culvert management technology by partnering in research activities with academia and

local corporate concerns.

CONCLUSION

Discussions with various DOTs around the country confirm a need to

better manage all types of highway assets. Since culverts typically go

unnoticed, there has not always been a sense of urgency to inspect or

manage these structures. But as recent high-profile failures on Interstate

and State highways around the Nation have occurred, the need to manage

these structures has become apparent. 

There are several keys to a high-quality, comprehensive management

system applicable to culverts and drainage structures. Based on AASHTO

guidelines, the purpose of a CMS is to use economic and engineering data

to help determine the best actions to perform on the network of culverts

over a period of time. An effective CMS includes these key components:

• Inventory.

• Inspection and condition appraisal.

• Cost data:

– Agency costs (i.e., maintenance, repair, and replacement).

– User costs.

Replacement/Widening

Repairs

Preventive Maintenance

Other

$15,000

$5,000

$450,000

$30,000

Figure 13. Shelby County Highway Department average annual culvert budget.
35

• Deterioration models.

• Optimization models.

• Feasible actions and work needs.

• Scheduling.

• Reporting.

Although many DOTs have some form of CMS in place or under

development, not all systems have all of the key components. FHWA has

taken an initial step toward helping DOTs manage their culvert inventory.

In October 2001, FHWA released CMS software along with a user’s 

manual. The purpose of this program is to provide a tool to facilitate the

coordination of maintenance and repair or replacement operations on a

system-wide basis.

Many States have expressed interest in the FHWA CMS. The University

Transportation Center of Alabama (UTCA) along with the SCHD has

sponsored implementation seminars for the FHWA CMS software. The

target audience of these seminars is county and city engineers, maintenance

personnel, and contractors. In addition to discussing culvert inspection

techniques and design philosophies, the seminar participants receive a copy

of the FHWA CMS software and manual. Part of the seminar demonstrates

how to build a culvert database using this software. Following the seminars,

a written report documents the outcomes, participants’ comments and

questions, and recommendations. One recommendation was to update 

and enhance the existing software and to fix any errors that are discovered.

Currently, FHWA is not actively supporting the maintenance of this program. The UTCA supports the concept that FHWA, through its Office 

of Asset Management, take ownership of the distribution, maintenance,

and future enhancements of the CMS. 

According to a survey of State DOT culvert management programs,

many States are not using any type of formal management system for

structures under 20 ft in length. DOTs who do use a system vary widely 

in the ways that they inspect, inventory, budget, and make decisions, not

only from State to State but also within different divisions of the same

agency. 

Although many States recognize the importance of culverts and

drainage structures, the lack of an actively promoted CMS and a current

culvert inspection course could be a reason that more resources are not

dedicated to culvert management. These facts have been taken into 

consideration by FHWA. As a result, FHWA will begin development 
36

of new culvert inspection training material and an updated and enhanced

FHWA CMS.

An effective CMS helps highway agencies to enhance highway safety,

use resources more efficiently, and preserve public assets:

• With the increased systematic attention to culvert inspection that

accompanies use of a CMS, structures in need of repair or replacement

can be identified before their condition is a risk for catastrophic failure. 

• The prioritization of rehabilitation, repair, and replacement needs

offered by a CMS helps agencies to optimize their use of the limited

human and financial resources they have available. 

• Finally, a CMS can help agency decision makers preserve the Nation’s

investment in highway infrastructure as they decide how best to spend

resources to maintain culverts throughout the highway network.
Further Information

Carl M. Highsmith

Federal Highway Administration

Project Delivery Team Leader

Louisiana Division

Baton Rouge, LA 70808

225-757-7615

carl.highsmith@dot.gov 

Bonnie Peterson

Minnesota Department of 

Transportation

HYDINFRA Coordinator

3485 Hadley Avenue N.

Oakdale, MN 55128

651-747-2166

bonnie.peterson@dot.state.mn.us

Thomas C. Grimes, P.E.

Shelby County Highway Department

Chief Engineer

506 Highway 70

Columbiana, AL 35051

205-669-3880

tgrimes@shelbycountyalabama.net

Joe Miller, P.E.

Maryland State Highway 

Administration

Office of Bridge Inspection and 

Remedial Engineering Division

707 North Calvert Street

Baltimore, MD 21202 

410-545-8311

jmiller5@sha.state.md.us

Karuna Pujara

Maryland State Highway 

Administration

Office of Highway Development

707 North Calvert Street

Baltimore, MD 21202 

410-545-8390

kpujara@sha.state.md.us

Stacey N. Glass, P.E.

Alabama Department of 

Transportation

Assistant State Maintenance Engineer

Management & Training

1409 Coliseum Boulevard

Montgomery, AL 36110

334-242-6277

glasss@dot.state.al.us

Eric Brown

Federal Highway Administration

Resource Center

Hydraulics Engineer

10 South Howard Street, Suite 4000

Baltimore, MD 21201

410-962-3743

eric.brown@dot.gov

Quality assurance statement: The Federal

Highway Administration (FHWA) provides 

high-quality information to serve Government,

industry, and the public in a manner that 

promotes public understanding. Standards and

policies are used to ensure and maximize the

quality, objectivity, utility, and integrity of its

information. FHWA periodically reviews quality

issues and adjusts its programs and processes

to ensure continuous quality improvement.
Office of Asset Management

Federal Highway Administration

U.S. Department of Transportation

400 Seventh Street, SW, HIAM-30

Washington, DC 20590

Telephone: 202-366-0392

Fax: 202-366-9981

www.fhwa.dot.gov/infrastructure/asstmgmt

FHWA IF-07-032